1. Field
Apparatuses and methods consistent with exemplary embodiments relate to a communication device and a method for generating a beamforming link.
2. Description of the Related Art
Technological progress relating to wireless networks and a corresponding increase in demand for bulk multimedia data transmission have provided an impetus for research relating to an effective transmission method in a wireless network environment. Furthermore, wireless transmission of high-quality video, such as Digital Video Disk (DVD) images and High Definition Television (HDTV) images, between various home devices is increasing.
Recently, technology relating to transmitting a large amount of data in a wireless home network has been developed. In particular, this technology, referred to as Millimeter Wave (mmWave), uses a 60 GHz band of an electronic wave for which a physical wavelength is generally measured in millimeters (i.e., an electronic wave having a frequency within the range of 30 GHz to 300 GHz) to transmit a large amount of data. In the past, this frequency range has been used to a limited extent by communication providers, for electronic wave astrology, and for vehicle anti-collision applications, because it is an unlicensed band. The 60 GHz band has a channel bandwidth of 2.16 GHz in the standard. Thus, mmWave has a much greater carrier frequency and channel bandwidth than other frequency bands. Accordingly, the use of a millimeter-wave signal having a wavelength measured in millimeter units creates the possibility of a very high data rate, on the order of several-Gbps, and a possibility of an implementation of a single chip which includes an antenna having a size which is 1.5 mm or less.
In particular, research has recently been conducted into transmission of non-compressed audio or video data (hereinafter, non-compressed data) between wireless devices by using a relatively high bandwidth within the millimeter wave range. Compressed data may be compressed in a lossy way, by, for example, removing portions less sensitive to human visual or auditory sense by using processes such as motion compensation, Discrete Cosine Transform (DCT), quantization, and variable length coding, while non-compressed data may include, for example, digital values (e.g., R, G, and B components) which indicate respective states of pixel components.
FIG. 1 is a schematic configuration diagram of a wireless network system which includes a wireless network coordinator 10 and wireless network stations 20.
The wireless network coordinator 10 adjusts a bandwidth allocation for each of the wireless network stations 20 in a wireless network by transmitting a beacon frame. In particular, one or more wireless network stations 20 forming the wireless network refer to the received beacon frame, thereby waiting to be allocated a bandwidth, or transmitting data to another station through an allocated bandwidth when the bandwidth is allocated thereto. The wireless network is formed based on a beacon interval which includes at least one Data Transfer Time (DTT), which may be classified into a scheduled Service Period (SP), i.e., a time period scheduled to allocate a bandwidth to a specific wireless network station 20 in the wireless network, and a Contention-Based Access Period (CBAP), i.e., a time period which is bandwidth-allocated to one wireless network station 20 that selected through contention from among wireless network stations 20 in the wireless network. The DTT indicates a predetermined time period during which data is transmitted and received between the wireless network stations 20 in the wireless network. A wireless network station 20 may transmit data during a CBAP by winning contention against other wireless network stations 20, or may transmit data during an SP allocated thereto.
In accordance with the mmWave technology, which enables data to be transmitted with a channel bandwidth of 2.16 GHz by using a carrier frequency of 60 GHz, directional communication may be required. In particular, data communication may be achieved by arranging antennas included in a transmission station and a reception station to face each other, and in this case, it is preferable to perform beamforming for synchronizing a direction of an electronic wave.
It may be understood that a purpose of the beamforming is to adjust directions of electronic waves transmitted and received by antennas included in a transmission station and a reception station so that the electronic wave directions match each other, in order for data to be smoothly transmitted and received in a high frequency band.
Conventionally, in a beamforming operation between a transmission station and a reception station, each having a plurality of antennas, a beamforming link may be generated for any respective pair of the respective pluralities of antennas of each of the transmission station and the reception station.
In particular, because the beamforming link is generated for only one of the plurality of antennas of each of the transmission station and the reception station, the other antennas of the transmission station and the reception station cannot be used in a practical manner.